Thermal Performance of Double-Pane Lightweight Steel Framed Walls with and without a Reflective Foil

Abstract

One strategy to increase energy efficiency of buildings could be the reduction of undesirable heat losses by mitigating the heat transfer mechanisms across the building envelope. The use of thermal insulation is the simplest and most straightforward way to promote thermal resistance of building elements by reducing the heat transfer by conduction. However, whenever there is an air cavity, radiation heat transfer could be also very relevant. The use of thermal reflective insulation materials inside the air gaps of building elements is likewise an effective way to increase thermal resistance without increasing weight and wall thickness. Some additional advantages are its low-cost and easy installation. In this work, the performance of a thermal reflective insulation system, constituted by an aluminium foil placed inside an air cavity between a double pane lightweight steel framed (LSF) partition, is experimentally evaluated for different air gap thicknesses, ranging from 0 mm up to 50 mm, with a step increment of 10 mm. We found a maximum thermal resistance improvement of the double pane LSF walls due to the reflective foil of around +0.529 m2∙°C/W (+21%). The measurements of the R-values were compared with predictions provided by simplified models (CEN and NFRC 100). Both models were able to predict with reasonable accuracy (around ±5%) the thermal behaviour of the air cavities within the evaluated double pane LSF walls.

The Relevance of Surface Resistances on the Conductive Thermal Resistance of Lightweight Steel-Framed Walls: A Numerical Simulation Study

“…The authors already have a large degree of experience in using three of these computational tools, as can be verified in the following published papers, regarding THERM [18,[20][21][22][23][34][35][36][37][38][39][40], ANSYS [21,22,34,38,39,41,42] and PSIPLAN [12,[43][44][45][46][47][48][49]. Only the FLIXO software is being used by the authors for the first time, but with excellent results, as can be checked afterwards.…”

Thermal Performance Improvement of Double-Pane Lightweight Steel Framed Walls Using Thermal Break Strips and Reflective Foils

“…Three configurations for the localization of the TB strips were considered (Figure 2): (i) along the inner steel stud flange (inner wall pane); (ii) along the outer steel stud flange (outer wall pane); (iii) on both steel stud flanges. Furthermore, the reflective foils tested are made of aluminium with an emissivity equal to 0.05 [23,24]. Regarding the localization of the reflective foils, three configurations were considered (Figure 2): (i) along the inner side of the air cavity; (ii) along the outer side of the air cavity; (iii) along both sides of the air cavity.…”

“…Recently, Santos and Ribeiro [24] studied the thermal performance of double-pane lightweight steel-framed walls with and without a reflective foil. This assessment was mainly experimental under laboratory-controlled conditions, but the measurements were compared with 2D finite element numerical simulations.…”

“…Finally, the main conclusions of this research work are summarized. Notice, that the various scenarios evaluated in this research work were based on previous papers from authors, namely reference [24] for the aluminium reflective foil scenarios and reference [17] for the thermal break strips.…”

Recovery of Mineral Wool Waste and Recycled Aggregates for Use in the Manufacturing Processes of Masonry Mortars

“…However, there is no doubt that the building sector is a key player in the fight against climate change [4]. Buildings are currently responsible for the consumption of more than 36% of global CO 2 emissions and generate more than 30% of solid waste in the European Union [5,6]. For this reason, it is necessary to promote actions that are committed to the incorporation of circular economy criteria in the construction industry.…”